I really tried and tried to get along with the traditional split finger style and just never felt comfortable with it. Then I switched to 2 fingers under, not 3 and it felt so much better. My groups improved drastically and I never went back.
Back to Richard's question, I'm not an expert by any means, but I haven't noticed any difference from one to the other and it hasn't hurt my bow in performance or physically. I don't notice any difference in sound either, it's whisper quiet either way.........at least as far as my ears can tell?